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Upper Gastro-intestinal Endoscopy (OGD)

This is a procedure where an appropriately trained healthcare professional (some of the best endoscopists are nurses rather than doctors) uses a flexible tube with a light source and camera at one end a video screen at the other to examine the lining of the oesophagus, stomach and the first part of the small bowel known as the duodenum. In order to safely undergo this procedure patients need to avoid food for a period of at least 5-6 hours to ensure the stomach is empty.

The endoscope can also be used to take biospies (tiny pieces of tissue just a couple of millimetres in diameter), or to apply therapy. Therapy may include measures to stop bleeding, open up a narrowing (dilation of a stricture), remove a polyp (a, usually benign, growth),  or insert a feeding gastrostomy, amongst other interventions. A gastroscope can also be used to remove a foreign body if indicated.

Usually endoscopes are between 8 to 9.5mm in diameter and are approximately 1.2 metres long (although not all of this usually goes into the patient). Endoscopes tend to have at least one “working channel” and a port for suction (sucking fluid or debris up the scope) and insufflation (blowing air or fluid in so the endoscopist can see where they are going!). Smaller and larger endoscopes are available for specific tasks. Upper GI endoscopy is usually undertaken using local anaesthetic (xylocaine) throat spray, or sedation, or occasionally a combination of the two


As one might expect having a tube passed over the back of the throat may cause some discomfort, but it should not be painful. Many patients do gag, but only 1 in three to four hundred patients do not manage to pass the tube into the gullet. As with any procedure there are some risks, most people feel discomfort. There is a small risk of damage to the mouth or to dentition, roughly 1 in a thousand. There is a risk of approximately one in two to five thousand of causing a perforation or bleeding during a normal procedure. These risks are obviously increased if the patient is known to have bleeding problems or if there procedure involves more complicated interventions, such as either to stretch a narrowing or treat a particular problem. There is a small risk of missing a pathology that would normally be expected to be identified. Rarely vomiting and aspiration may occur if the stomach has not been properly emptied (either because patients have eaten or drunk prior to the procedure or if the stomach is not working properly).  If sedation is given there are some risks from over-sedation.

Diagramatic representation of an upper GI Endoscopy
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Patient undergoing an upper GI Endoscopy
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